This invention relates to a composite wafer carrier designed for the transportation, storage, and processing of semiconductor wafer disks used in the production of integrated circuit components.
The processing of wafer disks into integrated circuit chips often involves several steps where the disks are repeatedly processed, stored and transported. Due to the delicate nature of the disks and their extreme value, it is vital that they are properly protected throughout this procedure. One purpose of a wafer carrier is to provide this protection. Additionally, since the processing of wafer disks is generally automated, it is necessary for disks to be precisely positioned relative to the processing equipment for the robotic removal and insertion of the wafers. A second purpose of a wafer carrier is to is to securely hold the wafer disks during transport.
The conventional wafer carrier is a single molded part generally comprising a front end having an H-bar interface portion, a back end having a panel, and sidewalls having slots and lower curved or converging portions following the curvature of the wafers, and with an open top and open bottom. These designs present problems in both their versatility and manufacture. When an adjustment needs to be made to a single-mold carrier's specifications the old mold or a portion thereof is typically modified or scrapped and a new mold or portion thereof tooled. The individual unchanged portions of the carrier typically cannot be separately molded and stockpiled for future assembly. Additionally, larger volume and more complex molded parts increase the possibility that warping or other structural problems will occur, thus affecting product quality and consistency. Consequently, single-mold integral wafer carriers have inherent inefficiencies.
Specifications which may be desirable to change on wafer carriers include the type of plastic, equipment interfaces, static dissapative characteristics, and wafer positioning and spacing.